stage i her2 positive invasive breast cancer de-escalation study(iris)

Conditions: Breast Cancer

Summary: this is an open label, phase ii study evaluating the efficacy and safety of trastuzumab combined with oral chemotherapy or endocrine therapy in patients with her-2 positive stage i breast cancer.

this study has two cohorts. in cohort a, patients who met the inclusion criteria(er，pr\<10%, t≤2cm or er,pr ≥10% 1cm\<t≤2cm）would be given capecitabine for 6 cycles with standard trastuzumab for 1 year, in which hr+ patients would be given endocrine therapy for 5 years. in cohort b, patients who met the inclusion criteria(er,pr ≥10% t≤1cm) would be given endocrine therapy (premenopausal: tamoxifen or toremifene; postmenopausal: letrozole or anastrozole or exemestane) combined with standard trastuzumab for 1 year and complete endocrine therapy for 5 years.

Eligibility criteria:
inclusion criteria: * females 18-70 years old; * pathological confirmed of stage i breast cancer: histologically confirmed that the longest diameter of invasive cancer is no more than 2cm and the lymph node is negative (n0); * in iris-a cohort, if a patient is hr negative(er/pr\<10%), the longest diameter of invasive cancer could not exceed 2cm; while if a patient is hr positive(er and/or pr ≥10%）,the longest diameter of invasive cancer is greater than 1cm and no more than 2cm; * in iris-b cohort, a patient need to be hr positive (er and / or pr expression ≥10%) and the longest diameter of invasive cancer could not exceed 1cm; * the pathological type of immunohistochemistry must meet the following conditions: her-2 (3+) or her-2 (0-2 +) with fish detection is amplified; * for patients with invasive lesions on both sides, if both lesions are her-2 positive and meet the tumor size requirements, then can be enrolled; * has adequate organ function meeting the following criteria: (1) adequate bone marrow function: hemoglobin ≥ 90 g/l (no blood transfusion within 14 days); absolute neutrophil count ≥ 1.5 x 109 /l; platelet count ≥ 100 \* 109 /l; (2)adequate liver and kidney function: alanine aminotransferase (alt) ≤ 3×upper limit of normal (uln), aspartate aminotransferase (ast) ≤ 3×uln, total bilirubin (tbil)≤ 1.5×uln, serum creatinine ≤ 1×uln#and with endogenous creatinine clearance rate of \>50 ml/min (cockcroft-gault formula); * lvef\>50%; * the patient voluntarily joined the study, signed the informed consent form, had good compliance, and cooperated with the follow-up. exclusion criteria: * has received neoadjuvant therapy (include chemotherapy, targeted therapy, radiotherapy or endocrine therapy; * has previous history of additional malignancy, with the exception of adequately treated basal cell carcinoma and cervical carcinoma in situ; * has metastic (stage 4) breast cancer; * pregnant or breast feeding women, or women of childbearing age who cannot practice effective contraceptives; * patients participating in other clinical trials at the same time; * has severe organ dysfunction (cardiopulmonary liver and kidney) insufficiency, left ventricular ejection fraction (lvef) \ 150/90mmhg, myocardial infarction, or cerebral blood vessel); diabetic patients with poor blood glucose control; patients with severe hypertension; * has severe or uncontrolled infection; * has a history of psychotropic substance abuse and were unable to abandon drug habits, or those with history of mental disorders; * the researchers considered patients to be unsuitable for the study.